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Dive into the research topics where Margaret K. Vandervoort is active.

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Featured researches published by Margaret K. Vandervoort.


Neurology | 1990

Interrater variability with the Expanded Disability Status Scale (EDSS) and Functional Systems (FS) in a multiple sclerosis clinical trial

John H. Noseworthy; Margaret K. Vandervoort; C. J. Wong; George C. Ebers

We describe the interrater variability in the Expanded Disability Status Scale (EDSS) and Functional Systems (FS) in a multiple sclerosis clinical trial. Two physicians blinded to their previous assessments and to each others scores consecutively examined 168 patients (545 paired examinations). Perfect agreement on the assignment of the disability scores ranged from 48% (cerebellar functional group) to 69% (EDSS and pyramidal functional group). Only 31% to 62% of this agreement occurred independently of that expected by chance (kappa). With the exception of the cerebellar and sensory functional groups, agreement within 1 step occurred in at least 92% of cases. These findings suggest that differences of a single step on these scales may not reflect an important functional change. We recommend that at least a 2-step change (1.0 point on the EDSS and 2 points on the FS) is needed to be confident of an important change in the degree of disability or response to treatment in this disease.


Clinical Gastroenterology and Hepatology | 2008

Treatment of Active Crohn's Disease With MLN0002, a Humanized Antibody to the α4β7 Integrin

Brian G. Feagan; Gordon R. Greenberg; Gary Wild; Richard N. Fedorak; Pierre Paré; John W.D. McDonald; Albert Cohen; Alain Bitton; Jeffrey P. Baker; Réjean Dubé; Steven B. Landau; Margaret K. Vandervoort; Asit Parikh

BACKGROUND & AIMS Selective blockade of lymphocyte-vascular endothelium interactions in the gastrointestinal tract is a promising therapeutic strategy for inflammatory bowel disease. This randomized, double-blind, controlled trial assessed the efficacy and safety of MLN0002, a monoclonal antibody targeting the alpha4beta7 integrin, in patients with active Crohns disease. METHODS Patients were randomized to receive MLN0002 2.0 mg/kg (n = 65), MLN0002 0.5 mg/kg (n = 62), or placebo (n = 58) by intravenous infusion on days 1 and 29. The primary efficacy end point was clinical response (>or=70-point decrement in the Crohns Disease Activity Index [CDAI] score) on day 57. Secondary end points were the proportions of patients with clinical remission (CDAI score <or=150) and with an enhanced clinical response (>or=100-point decrement in CDAI). Human anti-human antibody levels were measured. RESULTS Clinical response rates at day 57 were 53%, 49%, and 41% in the MLN0002 2.0 mg/kg, MLN0002 0.5 mg/kg, and placebo groups. Clinical remission rates at day 57 were 37%, 30%, and 21%, respectively (P = .04 for the 2.0 mg/kg vs placebo comparison). At day 57, 12% and 34% of patients in the 2.0- and 0.5-mg/kg groups had clinically significant human anti-human antibody levels (titers > 1:125). There was one infusion-related hypersensitivity reaction. The most common serious adverse event was worsening of Crohns disease. CONCLUSIONS This phase 2 study was suggestive of a dose-dependent beneficial effect of MLN0002 therapy on clinical remission. MLN0002 was well tolerated in patients with active Crohns disease.


JAMA | 2008

Omega-3 Free Fatty Acids for the Maintenance of Remission in Crohn Disease: The EPIC Randomized Controlled Trials

Brian G. Feagan; William J. Sandborn; Ulrich Mittmann; Simon Bar-Meir; Geert R. D'Haens; Marc Bradette; Albert Cohen; Chrystian Dallaire; Terry Ponich; John W.D. McDonald; Xavier Hébuterne; Pierre Paré; Pavel Klvana; Yaron Niv; Olga Alexeeva; Alaa Rostom; Gediminas Kiudelis; Johannes Spleiss; Denise Gilgen; Margaret K. Vandervoort; Cindy J. Wong; Guangyong Zou; Allan Donner; Paul Rutgeerts

CONTEXT Maintenance therapy for Crohn disease features the use of immunosuppressive drugs, which are associated with an increased risk of infection. Identification of safe and effective maintenance strategies is a priority. OBJECTIVE To determine whether the oral administration of omega-3 free fatty acids is more effective than placebo for prevention of relapse of Crohn disease. DESIGN, SETTING, AND PATIENTS Two randomized, double-blind, placebo-controlled studies (Epanova Program in Crohns Study 1 [EPIC-1] and EPIC-2) conducted between January 2003 and February 2007 at 98 centers in Canada, Europe, Israel, and the United States. Data from 363 and 375 patients with quiescent Crohn disease were evaluated in EPIC-1 and EPIC-2, respectively. INTERVENTIONS Patients with a Crohns Disease Activity Index (CDAI) score of less than 150 were randomly assigned to receive either 4 g/d of omega-3 free fatty acids or placebo for up to 58 weeks. No other treatments for Crohn disease were permitted. MAIN OUTCOME MEASURE Clinical relapse, as defined by a CDAI score of 150 points or greater and an increase of more than 70 points from the baseline value, or initiation of treatment for active Crohn disease. RESULTS For EPIC-1, 188 patients were assigned to receive omega-3 free fatty acids and 186 patients to receive placebo. Corresponding numbers for EPIC-2 were 189 and 190 patients, respectively. The rate of relapse at 1 year in EPIC-1 was 31.6% in patients who received omega-3 free fatty acids and 35.7% in those who received placebo (hazard ratio, 0.82; 95% confidence interval, 0.51-1.19; P = .30). Corresponding values for EPIC-2 were 47.8% and 48.8% (hazard ratio, 0.90; 95% confidence interval, 0.67-1.21; P = .48). Serious adverse events were uncommon and mostly related to Crohn disease. CONCLUSION In these trials, treatment with omega-3 free fatty acids was not effective for the prevention of relapse in Crohn disease. TRIAL REGISTRATION clinicaltrials.gov Identifiers: EPIC-1: NCT00613197, EPIC-2: NCT00074542.


Hypertension | 2009

A Simplified Approach to the Treatment of Uncomplicated Hypertension: A Cluster Randomized, Controlled Trial

Ross D. Feldman; Guang Y. Zou; Margaret K. Vandervoort; Cindy J. Wong; Sigrid Nelson; Brian G. Feagan

Notwithstanding the availability of antihypertensive drugs and practice guidelines, blood pressure control remains suboptimal. The complexity of current treatment guidelines may contribute to this problem. To determine whether a simplified treatment algorithm is more effective than guideline-based management, we studied 45 family practices in southwestern Ontario, Canada, using a cluster randomization trial comparing the simplified treatment algorithm with the Canadian Hypertension Education Program guidelines. The simplified treatment algorithm consisted of the following: (1) initial therapy with a low-dose angiotensin-converting enzyme inhibitor/diuretic or angiotensin receptor blocker/diuretic combination; (2) up-titration of combination therapy to the highest dose; (3) addition of a calcium channel blocker and up-titration; and (4) addition of a non—first-line antihypertensive agent. The proportion of patients treated to target blood pressure (systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mm Hg for patients without diabetes mellitus or systolic blood pressure <130 mm Hg and diastolic blood pressure <80 mm Hg for diabetic patients) at 6 months was analyzed at the practice level. The proportion of patients achieving target was significantly higher in the intervention group (64.7% versus 52.7%; absolute difference: 12.0%; 95% CI: 1.5% to 22.4%; P=0.026). Multivariate analysis of patient-level data showed that assignment to the intervention arm increased the chance of reaching the target by 20% (P=0.028), when adjusted for other covariates. In conclusion, the Simplified Treatment Intervention to Control Hypertension Study indicates that a simplified antihypertensive algorithm using initial low-dose fixed-dose combination therapy is superior to guideline-based practice for the management of hypertension.


Gastroenterology | 2008

A Randomized, Double-Blind, Sham-Controlled Study of Granulocyte/Monocyte Apheresis for Active Ulcerative Colitis

Bruce E. Sands; William J. Sandborn; Brian G. Feagan; Robert Löfberg; Toshifumi Hibi; Tao Wang; Lisa–Marie Gustofson; Cindy J. Wong; Margaret K. Vandervoort; Stephen B. Hanauer

BACKGROUND & AIMS Activated granulocytes and monocytes/macrophages are implicated in the pathogenesis of ulcerative colitis. Open-label studies and clinical experience in Japan and Europe have suggested that granulocyte/monocyte apheresis is safe and effective in treating ulcerative colitis. METHODS We evaluated the efficacy of granulocyte/monocyte apheresis in a randomized, double-blind, sham-controlled trial in patients with active moderate-to-severe ulcerative colitis (Mayo score 6-11) in community-based and tertiary care centers. As intervention, we used granulocyte/monocyte apheresis with the Adacolumn Apheresis System (JIMRO, Ltd, Takasaki, Japan) or sham apheresis in a 2:1 ratio for 9 weeks of treatment in a North American pivotal study (N = 168) and in a smaller, companion study of identical design conducted in Europe and Japan (N = 47). RESULTS In the pivotal study, clinical remission rates (Mayo score 0-2, with scores of 0 on rectal bleeding and 0 or 1 on endoscopic examination) were 17% and 11% for the granulocyte/monocyte apheresis (n = 112)- and sham-treatment groups, respectively (n = 56; P = .361). Clinical response (Mayo score reduction of >/=3 points from baseline) was observed in 44% and 39% of patients, respectively (P = .620). Similar changes were observed for the apheresis- and sham-treatment groups for endoscopic remission and response, and changes in Mayo and quality-of-life scores. The companion study and pooled data from both studies also yielded similar results. CONCLUSIONS In this study, granulocyte/monocyte apheresis was well tolerated but did not demonstrate efficacy for induction of clinical remission or response in patients with moderate-to-severe ulcerative colitis.


The Lancet | 2015

Early combined immunosuppression for the management of Crohn's disease (REACT): a cluster randomised controlled trial

Reena Khanna; Brian Bressler; Barrett G. Levesque; Guangyong Zou; Larry Stitt; Gordon R. Greenberg; Remo Panaccione; Alain Bitton; Pierre Paré; Severine Vermeire; Geert R. D'Haens; Donald G. MacIntosh; William J. Sandborn; Allan Donner; Margaret K. Vandervoort; Joan C. Morris; Brian G. Feagan

BACKGROUND Conventional management of Crohns disease features incremental use of therapies. However, early combined immunosuppression (ECI), with a TNF antagonist and antimetabolite might be a more effective strategy. We compared the efficacy of ECI with that of conventional management for treatment of Crohns disease. METHODS In this open-label cluster randomised controlled trial (Randomised Evaluation of an Algorithm for Crohns Treatment, REACT), we included community gastroenterology practices from Belgium and Canada that were willing to be assigned to either of the study groups, participate in all aspects of the study, and provide data on up to 60 patients with Crohns disease. These practices were randomly assigned (1:1) to either ECI or conventional management. The computer-generated randomisation was minimised by country and practice size. Up to 60 consecutive adult patients were assessed within practices. Patients who were aged 18 years or older; documented to have Crohns disease; able to speak or understand English, French, or Dutch; able to access a telephone; and able to provide written informed consent were followed up for 2 years. The primary outcome was the proportion of patients in corticosteroid-free remission (Harvey-Bradshaw Index score ≤ 4) at 12 months at the practice level. This trial is registered with ClinicalTrials.gov, number NCT01030809. FINDINGS This study took place between March 15, 2010, and Oct 1, 2013. Of the 60 practices screened, 41 were randomly assigned to either ECI (n=22) or conventional management (n=19). Two practices (one in each group) discontinued because of insufficient resources. 921 (85%) of the 1084 patients at ECI practices and 806 (90%) of 898 patients at conventional management practices completed 12 months follow-up and were included in an intention-to-treat analysis. The 12 month practice-level remission rates were similar at ECI and conventional management practices (66·0% [SD 14·0] and 61·9% [16·9]; adjusted difference 2·5%, 95% CI -5·2% to 10·2%, p=0·5169). The 24 month patient-level composite rate of major adverse outcomes defined as occurrence of surgery, hospital admission, or serious disease-related complications was lower at ECI practices than at conventional management practices (27·7% and 35·1%, absolute difference [AD] 7·3%, hazard ratio [HR]: 0·73, 95% CI 0·62 to 0·86, p=0·0003). There were no differences in serious drug-related adverse events. INTERPRETATION Although ECI was not more effective than conventional management for controlling Crohns disease symptoms, the risk of major adverse outcomes was lower. The latter finding should be considered hypothesis-generating for future trials. ECI was not associated with an increased risk of serious drug-related adverse events or mortality. FUNDING AbbVie Pharmaceuticals.


Inflammatory Bowel Diseases | 2014

Histologic evaluation of ulcerative colitis: a systematic review of disease activity indices.

Mahmoud Mosli; Brian G. Feagan; William J. Sandborn; Geert DʼHaens; Cynthia Behling; Keith J. Kaplan; David K. Driman; Lisa M. Shackelton; Kenneth A. Baker; John K MacDonald; Margaret K. Vandervoort; Karel Geboes; Barrett G. Levesque

Background:Ulcerative colitis (UC) is an idiopathic inflammatory disorder. Currently, the main goals of treatment are to induce and maintain clinical and/or endoscopic remission. However, evidence indicates that persistent disease activity on colonic biopsies in the setting of clinical or endoscopic remission is an independent predictor of poor outcomes. A number of previous studies have proposed histologic indices for use in specific trials of UC. The aim of this study was to systematically review the existing histological indices for UC and assess their potential use in both patient management and clinical trials. Methods:We performed a systematic review of histological indices evaluating disease activity in UC. MEDLINE (Ovid), EMBASE (Ovid), PubMed, the Cochrane Library (CENTRAL), and Digestive Diseases Week (DDW) abstracts of randomized and/or controlled trials clinical trials were searched from inception to February 2013 for applicable studies. Data from these studies were reviewed and analyzed. Results:After systematically applying inclusion criteria, we identified 108 scientific articles including 88 clinical studies and 21 related clinical reviews. Eighteen indices of histological activity in UC were identified and reviewed. Conclusions:Although multiple histological scoring indices for assessment of UC disease activity currently exist, none of these instruments were developed using a formal validation process and their operating properties remain poorly understood. Future studies are needed to address this deficiency.


Transfusion | 2007

A cluster-randomized controlled trial of a blood conservation algorithm in patients undergoing total hip joint arthroplasty.

Cindy J. Wong; Margaret K. Vandervoort; Suzanne L. Vandervoort; Allan Donner; Guangyong Zou; John K MacDonald; John Freedman; Keyvan Karkouti; Steven J. MacDonald; Brian G. Feagan

BACKGROUND: The optimum strategy for reducing allogeneic blood transfusion in patients undergoing total hip joint arthroplasty (THJA) is unknown.


Alimentary Pharmacology & Therapeutics | 2015

A retrospective analysis: the development of patient reported outcome measures for the assessment of Crohn's disease activity.

Reena Khanna; Guangyong Zou; Geert R. D'Haens; Brian G. Feagan; William J. Sandborn; Margaret K. Vandervoort; Robert L. Rolleri; Enoch Bortey; Craig Paterson; William P. Forbes; Barrett G. Levesque

The Crohns Disease Activity Index (CDAI) is a measure of disease activity based on symptoms, signs and a laboratory test. The US Food and Drug Administration has indicated that patient reported outcomes (PROs) should be the primary outcome in randomised controlled trials for Crohns disease (CD).


Gut | 2017

Development and validation of a histological index for UC

Mahmoud Mosli; Brian G. Feagan; Guangyong Zou; William J. Sandborn; Geert R. D'Haens; Reena Khanna; Lisa M. Shackelton; Christopher W Walker; Sigrid Nelson; Margaret K. Vandervoort; Valerie Frisbie; Mark A. Samaan; Vipul Jairath; David K. Driman; Karel Geboes; Mark A. Valasek; Rish K. Pai; Gregory Y. Lauwers; Robert H. Riddell; Larry Stitt; Barrett G. Levesque

Objective Although the Geboes score (GS) and modified Riley score (MRS) are commonly used to evaluate histological disease activity in UC, their operating properties are unknown. Accordingly, we developed an alternative instrument. Design Four pathologists scored 48 UC colon biopsies using the GS, MRS and a visual analogue scale global rating. Intra-rater and inter-rater reliability for each index and individual index items were measured using intraclass correlation coefficients (ICCs). Items with high reliability were used to develop the Robarts histopathology index (RHI). The responsiveness/validity of the RHI and multiple histological, endoscopic and clinical outcome measures were evaluated by analyses of change scores, standardised effect size (SES) and Guyatts responsiveness statistic (GRS) using data from a clinical trial of an effective therapy. Results Inter-rater ICCs (95% CIs) for the total GS and MRS scores were 0.79 (0.63 to 0.87) and 0.80 (0.69 to 0.87). The correlation estimates between change scores in RHI and change score in GS and MRS were 0.75 (0.67 to 0.82) and 0.84 (0.79 to 0.88), respectively. The SES and GRS estimates for GS, MRS and RHI were: 1.87 (1.54 to 2.20) and 1.23 (0.97 to 1.50), 1.29 (1.02 to 1.56) and 0.88 (0.65 to 1.12), and 1.05 (0.79 to 1.30) and 0.88 (0.64 to 1.12), respectively. Conclusions The RHI is a new histopathological index with favourable operating properties.

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Brian G. Feagan

University of Western Ontario

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Guangyong Zou

University of Western Ontario

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Reena Khanna

University of Western Ontario

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Cindy J. Wong

University of Western Ontario

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Larry Stitt

University of Western Ontario

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John W.D. McDonald

University of Western Ontario

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B. Feagan

Robarts Research Institute

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